HONEYWELL 51303940-150风扇,培训教程
闪存板上有高达1MB的闪存。闪存的工作原理类似EPROM，但可以通过软件擦除和重新编程。其组织形式为32位宽，但对于处理器来说，它看起来是64位宽。映射于读取可以是任何大小，包括突发传输，但是无论为传输指定的大小如何，写入总是32位宽。因此，软件应仅使用32位写传输。这段记忆由总线开关和内存大小、访问时间和写入控制可通过ROM控制寄存器（ROMCR）编程启用功能在总线开关中。
HONEYWELL 51303940-150风扇可以从处理器总线访问闪存只有无法从本地外围总线或VMEbus访问。车载DRAMMVME197LE板载DRAM（2组32MB内存，一个可选）已安装）使用1M x 4设备，大小为32MB，配置为256位宽的DRAM是四路交错的，以有效支持缓存突发周期。DRAM由DCAM和ECDM以及map控制DCAM中的解码器可以通过中的I2Cbus接口进行编程ECDM可适应不同的基址和大小。本地外围总线重置不会禁用板载DRAM。参考DCAM和MVME197LE、MVME197DP和MVME197SP Single中的ECDM章节板机程序员详细编程参考指南信息电池备份RAM和时钟MVME197LE上使用了MK48T08 RAM和时钟芯片。这个芯片提供时钟、振荡器、晶体、电源故障检测、内存写保护、8KB RAM和一个28针封装中的电池。时钟
以BCD 24小时格式提供秒、分钟、小时、天、日期、月份和年份总体安排28、29、（闰年）和30天月份的修正为自动生成。时钟不会产生中断。MK48T08是一个8位设备；但是，PCCCIP2提供的接口支持对MK48T08的8位、16位和32位访问。请参阅中的PCCCIP2章MVME197LE、MVME197DP和MVME197SP单板计算机有关详细信息，请参阅程序员参考指南和MK48T08数据表编程信息
Flash Memory
Up to 1MB of flash memory is available on the board. Flash memory works like
EPROM, but can be erased and reprogrammed by software. It is organized as
32 bits wide, but to the processor it looks as 64 bits wide. It is mapped at
location $FF800000. Reads can be of any size, including burst transfers, but
writes are always 32 bits wide, regardless of the size specified for the transfer.
For this reason, software should only use 32-bit write transfers. This memory
is controlled by the BusSwitch, and the memory size, access time, and write
enable capability can be programmed via the ROM Control Register (ROMCR)
in the BusSwitch. The flash memory can be accessed from the processor bus
only. It is not accessible from the local peripheral bus or VMEbus.
Onboard DRAM
The MVME197LE onboard DRAM (2 banks of 32MB memory, one optionally
installed) is sized at 32MB using 1M x 4 devices and configured as 256 bits
wide. The DRAM is four-way interleaved to efficiently support cache burst
cycles. The DRAM is controlled by the DCAM and ECDM, and the map
decoders in the DCAM can be programmed through the I2Cbus interface in
the ECDM to accommodate different base address(es) and sizes. The onboard DRAM is not disabled by a local peripheral bus reset. Refer to the DCAM and
ECDM chapters in the MVME197LE, MVME197DP, and MVME197SP Single
Board Computers Programmer’s Reference Guide for detailed programming
information.Battery Backup RAM and Clock
The MK48T08 RAM and clock chip is used on the MVME197LE. This chip
provides a time of day clock, oscillator, crystal, power fail detection, memory
write protection, 8KB of RAM, and a battery in one 28-pin package. The clock
provides seconds, minutes, hours, day, date, month, and year in BCD 24-hour
format. Corrections for 28-, 29-, (leap year) and 30-day months are
automatically made. No interrupts are generated by the clock. The MK48T08
is an 8-bit device; however the interface provided by the PCCchip2 supports
8-, 16-, and 32-bit accesses to the MK48T08. Refer to the PCCchip2 chapter in
the MVME197LE, MVME197DP, and MVME197SP Single Board Computers
Programmer’s Reference Guide and to the MK48T08 data sheet for detailed
programming information
